Day of Happiness is celebrated on March 20, 2018. The International Day of Happiness is celebrated throughout the world on 20 March. It was established by the United Nations General Assembly on 28 June 2012. The International Day of Happiness recognizes the relevance of happiness and well-being as universal goals and aspirations in the lives of human beings.
Happiness is a mental or emotional state of well-being characterized by positive or pleasant emotions ranging from contentment to intense joy. Happiness is a fuzzy concept and can mean many things to many people. Part of the challenge of a science of happiness is to identify different concepts of happiness, and where applicable, split them into their components. (With material from: Wikipedia)